[en] In Finland the reactor pressure vessel at Loviisa-1 is to be annealed to remedy the embrittlement caused by neutron irradiation. The embrittlement can be detected by monitoring changes in the mechanical properties of the pressure vessel steel and welds from tensile test data, hardness and Charpy V-notch transition curves and fracture toughness results. Copper and phosphorus impurities may be the cause of the sensitivity to the neutron irradiation. The annealing programme - a week of heat treatment at 450^oC - reduces the effect of irradiation on the shift of the brittle-ductile transition temperature. Other annealing programmes have taken place at the Bohunice and Marble Hill reactors and this may become a routine way of prolonging the life of the reactor. (UK)

[en] The effect of neutron radiation on the reactor pressure vessel and the influence of annealing performed to eliminate this effect are explained. Some practical examples are given. A simple heat treatment at 450 degC for 168 h is sufficient to eliminate a major fraction of the radiation effect in the displacement of the transition temperature from the brittle state to the tough state. Some observations indicate that at this temperature, excessive energy recovery takes place at the upper toughness limit in the Charpy diagram. The annealing furnace manufactured by the SKODA company is described. The furnace consists of heating elements in 13 zones and 5 heating sections. The maximum power of each element is 75 kW, the total power of the furnace is 975 kW. The annealing procedure and its results are briefly outlined for the reactor pressure vessel at unit 2 of the Jaslovske Bohunice NPP. Reactor pressure vessel annealing is proposed for the Marble Hill NPP which has been shut down. Preparatory activities for annealing are also under way at the Loviisa NPP. (J.B.)

[en] A quantitative in vitro immune assay based on the classical chromium release assay has been developed to detect immune responses directed against alien antigens expressed by the developing foetus and present on the maternal-facing surface of the human placenta. A plasma membrane fraction from the surface of the placenta was prepared and the vesicles thus formed were radiolabelled with ⁵¹Cr. The ⁵¹Cr-labelled vesicles, by various criteria, were found to be suitable for use as targets in a release assay. Further, by means of experimentally immunised animals, the target membranes were shown to be capable of detecting both cellular and humoral anti-placental activity. (Auth.)

[en] This presentation described the implications of flare research project findings with reference to reduced combustion efficiency, stack plume down wash and minor species. A plume model shows that reduced combustion efficiency decreases the energy available for plume rise. Reduced combustion may therefore decrease H₂S to SO₂ conversion. Stack plume down wash can decrease plume rise under high wind speed conditions, and in extreme cases can also preclude any plume rise. Minor species include vapour phase emissions of polynuclear aromatic hydrocarbons (PAH), benzene, toluene, ethyl-benzene and xylenes (BTEX), and aldehydes. They also include particulate phase emissions such as soot and PAH. Observed concentrations of minor species were presented along with predicted vapour phase concentrations and particulate phase emissions. The standard modelling approaches used in this study included the Gaussian plume model, flame height, plume rise and dispersion. figs

[en] A study has been carried out into the feasibility of developing an electricity trading mechanism which would allow consumers to purchase electricity which has been derived from renewable energy resources. This study was part funded by the European Commission (ALTENER), the Department of Trade and Industry and a number of private sector companies. The trading mechanism is known as the Green Pool. As a result of the findings of this study discussions are being held with potential generators and suppliers to establish a Green Pool plc. The aim is to encourage the development of new renewable energy projects outside the NFFO and SRO schemes. The Green Pool plc will be owned by the generators and its main objective will be to market the electricity produced by its members. (Author)

[en] The work described in this report forms a continuation to that given in the Department of the Environment Report Ref - DOE/RAS/96.012 RW 8/6/65 Sector C. The studies reported previously described the occurrence of elevated levels of outdoor gamma-ray background radiation and identified these as being due to the presence of gamma-ray emitting daughters of radon in the atmosphere. This report continues this previous work and includes data from two custom designed and built low resolution gamma-ray spectrometers. One was operated at Hurn Airport, Bournemouth and the other at the Harwell Laboratory together with a continuation of the high resolution spectrometer at Harwell. The programme was able to show that the low resolution NaI spectrometers developed could be operated remotely for long periods of time without significant user intervention and provide reliable and very sensitive indication of high radon events. The monitors described could be incorporated into the existing RIMNET system to allow real time confirmation of radon events. (author)

[en] Syncrude Canada is the largest oil sands recovery and upgrading facility in the world. Activities such as mining, extraction, upgrading and waste discharge into large holding ponds provides the potential for substantial fugitive emissions of volatile organic hydrocarbons and reduced sulphur compounds. A detailed study was performed during worst case conditions to evaluate the incremental downwind concentrations potentially arising from site activities. Flux monitoring was coupled with mass transfer modeling and upwind/downwind profiling to evaluate the emission rates from specific sources. Site export due to fugitive sources was measured to be ca. 600 g/s for VOC and 1.9 g/s for H₂S. Significant emissions of other reduced sulphur compounds were also found. The main tailings pond (22 sq km) was found to be the major emitter for both classes of compounds. Dispersion modeling using on site meteorological information measured during the study period was coupled with an area source dispersion model to evaluate concentrations at a point 5 km outside the plant boundary, representing the nearest residential community. Concentrations predicted (and measured) for VOCs and reduced sulphur compounds were at low μg/m³ and ng/m³ levels, respectively

[en] The last several years have witnessed the completion of several large-scale red-shift surveys of galaxies, which have greatly increased our knowledge of the large-scale distribution of galaxies, and have shown that the superclustering phenomenon is widespread and accompanied by large holes in space that appear to be quite deficient in galaxies. The extreme lumpiness of our local Universe presents a challenge to all current theories of galaxy and cluster formation. A comparison with existing n-body simulations, results in a poor match to the observations, indicating either that the initial conditions are incorrect or that additional input physics must be specified. With the large CfA red-shift survey complete to magnitude 14.5 at high Galactic latitude, it is possible to determine dynamical masses of small groups as well as large clusters, and the data set provides critical parameters for the mass measurement of the entire Local Supercluster. A trend of increasing mass:light ratio with scale size of measurement emerges from these studies, an effect that implies that dissipative processes probably played a major role in the formation of galaxies and clusters. (author)

[en] The United Kingdom is engaged in an initiative to invest in the growth of city centres and to establish higher housing densities for new developments. An increase in energy and resources will be needed to supply these built environments. The Climate Change Act in the United Kingdom stipulates that along with this growth, an 80 per cent reduction in carbon dioxide (CO₂) emissions from 1990 levels should be met by 2050. While part of the expected reductions in buildings will come from energy efficiency, the rest will come from low and zero carbon (LZC) energy generation. LZC technologies must be developed using zero carbon on-site or near-site sources. This paper considered the feasibility of meeting the energy demand of urban buildings and the ability to meet zero carbon via on-site sources and the physical and technical limitations associated with this. It defined what sources of energy should be considered as on-site incident resources. The on-site incident energy yield was then assessed and compared against the annual energy demand for a range of urban densities. A mixed-use development site, typical of southeast England was used to assess the availability of on-site incident energy against which the urban densities energy demands are compared. The on-site energy sources considered in this study were meaningfully quantified and qualified in order to determine to what extent they can supply energy to an urban site, not just reduce CO₂ emissions. Energy demand models were used along with solar radiation estimates for urban areas. The study showed that given the projected energy demand, meeting on-site annual energy requirements sustainably is achievable even at high urban densities, but the demand may be greater than the yield in a given month. The study also showed that sharing infrastructure allows for energy to be better balanced to serve the urban form, particularly in heating systems. 16 refs., 3 tabs., 7 figs

[en] The contents of the rat cecum and, to a lesser extent, those of the small intestine, synthesized methylmercury from mercuric chloride labeled with Hg 203 in vitro under aerobic or anaerobic conditions. The rate of formation was approximately 18 ng/g cecal contents/20 hr. The synthesis of methylmercury was inhibited by antibiotics and by filtration of the cecal contents through membrane filters, indicating that the bacterial flora of the gut participates in the reaction. Pure cultures of bacteria, isolated from the intestinal tract of the rat, could methylate mercuric chloride. It was estimated that the total amount of methylmercury synthesized from ingested inorganic mercury in man is approximately 400 ng/day